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DNA COMPUTING

G.Nageswara rao (08BQ1A1225)

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2

Outline of Lecture

What is DNA ?.

Instructions in DNA. Operations.

Pros and Cons.

Conclusions.

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What is DNA?

DNA stands for Deoxyribonucleic Acid

DNA represents the genetic blueprint of living creatures

DNA contains “instructions” for assembling

cells Every cell in human body has a complete set

of DNA

DNA is unique for each individual

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Double Helix

“Sides” 

Sugar-phosphate backbones

“ladders” 

complementary base pairs

Adenine & Thymine

Guanine & Cytosine

Two strands are held together by

weak hydrogen bonds between thecomplementary base pairs

Source: “Human Physiology: From Cells to System 

4th Ed.”, L. Sherwood, Brooks/Cole, 2001, C-3

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Instructions in DNA

Instructions are coded  in a sequence of the DNA

bases

A segment of DNA is exposed, transcribed and

translated to carry out instructions

Sequence to indicate the

start of an instruction

Instruction that triggers

Hormone injectionInstruction for hair cells

……… 

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Can DNA Compute?

DNA itself does not carry out any

computation. It rather acts as a massivememory.

BUT, the way complementary bases react

with each other can be used to compute

things.

Proposed by Adelman in 1994

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Operations

Meltingbreaking the weak hydrogen bonds in a double

helix to form two DNA strands which are

complement to each other

Annealing

reconnecting the hydrogen bonds betweencomplementary DNA strands

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Operations (Cont’d) 

Mergingmixing two test tubes with many DNA molecules

AmplificationDNA replication to make many copies of the

original DNA molecules

Selectionelimination of errors (e.g. mutations) and selection

of correct DNA molecules

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The Smallest Computer

The smallest programmable DNA computerwas developed at Weizmann Institute inIsrael by Prof. Ehud Shapiro last year

It uses enzymes as a program that processeson on the input data (DNA molecules).

http://www.weizmann.ac.il/mathusers/lbn/new_pages/Research_Biological.html

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Pros and Cons

+ Massively parallel processor

DNA computers are very good to solve Non-deterministic Polynomial problems such as

DNA analysis and code cracking.

+ Small in size and power consumption

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Pros and Cons (Cont’d) 

- Requires constant supply of proteins and

enzymes which are expensive- Errors occur frequently

a complex selection mechanism is required

and errors increase the amount of DNA

solutions needed to compute

- Application specific

- Manual intervention by human is required

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Conclusion

Many issues to be overcome to produce a

useful DNA computer.

It will not replace the current computers

because it is application specific, but has a

potential to replace the high-end research

oriented computers in future.

Nanotechnology?